JP3379148B2 - Cryogenic cooling device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryogenic cooling device used in a superconducting magnet device. This cryocooler
In particular, it is applicable as an on-vehicle cryogenic cooling device for cooling a superconducting magnet device mounted on a superconducting magnetic levitation railway vehicle (linear motor car).

[0002]

2. Description of the Related Art The one shown in FIG.
It is a circuit diagram of the conventional cryogenic cooling device shown in 48431 gazette. In the figure, reference numeral 1 is a compression piston of a refrigerator main body, 2 is a piston ring of the compression piston, 3 is a rod seal of the compression piston, 4 is a compression space, 5 is a first stage expansion piston, and 6 is a first stage expansion piston ring. , 7 is a radiator, 8 is a first stage regenerator, 9 is a first stage expansion cylinder, 10
Is a first stage expansion space, 11 is a second stage expansion piston, 12 is a second stage expansion piston ring, 13 is a second stage regenerator, 14
Is a second stage expansion cylinder, 15 is a second stage expansion space, 16 is a third stage expansion piston, 17 is a third stage expansion piston ring, 18 is a third stage regenerator, 19 is a third stage expansion cylinder,
Reference numeral 20 is a third-stage expansion space, 21 is a helium compressor main body forming a part of the JT circuit, 22 is a first JT heat exchanger, and 23
Is a second JT heat exchanger, 24 is the second stage expansion space 15
Section, a second precooling heat exchanger attached to the cylinder 14, 25 is a third JT heat exchanger, 26 is a third precooling heat exchanger attached to the cylinder 19 near the third stage expansion space 20 section, Reference numeral 27 is a fourth JT heat exchanger, 28 is a JT expansion valve, and 29 is a condensation heat exchanger arranged in the space inside the liquid helium tank.

The refrigerator body is composed of a three-stage, one-cylinder expander, and the refrigeration generated in the first-stage expansion space 10 is
The heat is transferred to the refrigerant in the JT circuit via the first JT heat exchanger 22. The freezing generated in the second expansion space 15 is the second
Heat is transferred to the refrigerant in the JT circuit via the pre-cooling heat exchanger 24. The refrigeration generated in the third expansion space 20 is also transferred to the refrigerant in the JT circuit via the third precooling heat exchanger 26. The helium gas sequentially cooled in each stage of the pre-cooling heat exchanger and each JT heat exchanger is partially liquefied at the JT expansion valve 28 to be a low-pressure cryogenic mist-like helium, and then to the condensing heat exchanger 29. Reach The helium gas around the outside of the condensing heat exchanger 29 touches the condensing heat exchanger portion 29 and is partly liquefied.

In addition to the conventional example shown in FIG.
The examples disclosed in Japanese Patent No. 1-8225 and Japanese Patent Publication No. 51-14168 disclose that a regenerator and an expansion space are connected by a heat transfer.

[0005]

Since the conventional cryogenic cooling device is constructed as described above, the refrigerating capacity of the third stage expansion section is affected by the temperature change of the second stage expansion section before it. Further, the refrigerating capacity of the second-stage expansion section is easily affected by the temperature change of the preceding first-stage expansion section.
That is, the refrigerating output of the three-stage expansion method is more unstable than that of the two-stage expansion method with respect to heat load fluctuations from the outside. Also,
Since the compression piston and the expansion piston of the refrigerator main body each have one cylinder, a large fluctuating load acts on the motor that rotationally drives the crankshaft that operates these cylinders. Therefore, it is necessary to use a bearing having a large load capacity in the drive unit and a large output motor as an output source.

The present invention has been made in order to solve the above problems, and an object thereof is to provide a cryogenic cooling device which requires less electric power, has high efficiency, has stable refrigerating output, and has small vibration noise. And

[0007]

In the cryogenic cooling device of the present invention, the compression part and the expansion part of the refrigerator main body are made to have two cylinders, the rotational phase angles of the cylinders are shifted, and the freeze extraction part is distributed to each cylinder. Use the means to make. Preferably, a means for providing a freezing take-out portion in the expansion cylinder and the cold storage portion and providing a heat exchange fin groove in a part of the inner diameter of the expansion cylinder is used.

Specifically, the present invention has a pair of refrigeration cycles in which the expansion section has a two-stage structure, and further, a first precooling heat in a heat exchange relationship with the first expansion section of one refrigeration cycle. An exchanger, a second pre-cooling heat exchanger in heat exchange relationship with the second expansion section,
And a cryogenic cooling device having a Joule-Thomson circuit having a second expansion section of the other refrigeration cycle and a third pre-cooling heat exchanger in a heat exchange relationship, and a liquid helium storage tank connected to the Joule-Thomson circuit. provide.

Further, according to the present invention, a vacuum heat insulating outer tank container having therein a liquid helium storage tank containing an object to be cooled, a refrigerator main body, and a vacuum heat insulating outer tank container connected to the refrigerator main body In a cryogenic cooling device having a Joule-Thomson circuit having an exchange-related pre-cooling heat exchanger, an expansion part of a refrigerator main body is a two-stage two-cylinder, and a first-stage expansion part and a second-stage expansion part of the first cylinder. And refrigeration generated in the second expansion section of the second cylinder is passed through the first pre-cooling heat exchanger, the second pre-cooling heat exchanger, and the third pre-cooling heat exchanger to form a refrigerant in a Joule Thomson (hereinafter referred to as JT) circuit. Provided is a cryogenic cooling device characterized in that heat is transferred to Preferably, a fourth precooling heat exchanger and a fifth precooling heat exchanger are provided in the second stage cold storage section of the first cylinder and the second stage cold storage section of the second cylinder of the refrigerator main body, and further, in the refrigerator. Grooves are provided inside the second stage expansion cylinder of the first cylinder and the second stage expansion cylinder of the second cylinder.

[0010]

[Operation] From the refrigerator main body which constitutes the pair of refrigeration cycles, J
The portion from which refrigeration is taken out to the T circuit is the first-stage expansion section of the first cylinder, followed by the second-stage expansion section in descending order of temperature, and then the second section.
Take it out from the second expansion section of the cylinder. Since refrigeration is not taken out from the first stage expansion section of the second cylinder, this section always provides a stable and constant temperature. Therefore, the second stage expansion section of the second cylinder is not affected by the temperature change from the first stage expansion section of the second cylinder, and it is possible to always transmit a stable refrigeration output to the JT circuit. Further, by appropriately shifting the crankshaft rotation phase angle of the two cylinders, torque fluctuation can be reduced to a minimum, so a large output motor is not required,
It requires less power. When the torque fluctuations are reduced, vibration noise from the bearing portion and the gear joint portion is also reduced. Also the first
Refrigeration is more effectively taken out from the second-stage cold storage section of each of the cylinder and the second cylinder, and fin grooves are provided in a part of the inner diameter of the expansion cylinder to improve the heat exchange efficiency of gas.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing its embodiments. FIG. 1 is a circuit diagram of a cryogenic refrigerating apparatus showing an embodiment thereof. The same or corresponding parts as those shown in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted. In the figure, 1a is the compression piston of the second cylinder of the refrigerator body, 2a is the piston ring, 4a is the compression space of the compression section,
Reference numeral 5a is a second cylinder first stage expansion piston, 6a is a second cylinder first stage expansion piston ring, 7a is a second cylinder radiator, 8a is a second cylinder first stage regenerator, and 9a is a second cylinder. First stage expansion cylinder of cylinder, 10a is first stage expansion space of second cylinder, 16a is second stage expansion piston of second cylinder, 17a is second stage expansion piston ring of second cylinder, and 18a is second cylinder. Is a second stage regenerator, and 19a is a second stage expansion cylinder of the second cylinder.

In FIG. 1, 20a is a second expansion space of the second cylinder, 22a is a first precooling heat exchanger attached to a cylinder 9 near the first expansion space 10 of the first cylinder, and 26a is the above-mentioned. The third precooling heat exchanger attached to the cylinder 19a in the vicinity of the second stage expansion space 20a, 30 is a superconducting magnet,
31 is liquid helium that cools the superconducting magnet, 32 is a liquid helium storage tank that stores the superconducting magnet and liquid helium, 3
3 is a heat shield plate, 34 is a vacuum insulation outer tank container, 35, 3
5a is a flexible seal for separating helium gas between the expansion section and the crankcase section, 36, 36a is a flexible seal for separating helium gas between the compression section and the crankcase section, 37,
37a is a guide piston for the expansion section, 38, 38a are guide pistons for the compression section, 39 and 39a are expansion section guide piston pins 40, 40a are the compression section guide piston pins, 4
1, 41a are connecting rods of the expansion part, 42, 4
Reference numeral 2a is a connecting rod of a compression portion, 43 is a crankshaft, 44 is a bearing for supporting the crankshaft, 4
5 is a crankcase.

In the cryogenic refrigeration system constructed as described above, the compression section and the expansion section of the refrigerating machine body constituting the refrigeration cycle are composed of two cylinders, and each cylinder has a different rotational phase angle. It is driven by one motor via one crankshaft 43. First stage expansion space 10
The refrigeration generated in 1st through the first pre-cooling heat exchanger 22a,
Heat is transferred to the refrigerant in the JT circuit. The refrigeration generated in the second expansion space 15 of the first cylinder is transferred to the refrigerant in the JT circuit via the second precooling heat exchanger 24. The refrigeration generated in the second-stage expansion space 20a of the second cylinder is the third pre-cooling heat exchanger 2
Heat is also transferred to the refrigerant in the JT circuit via 6a.

In order to further stabilize the refrigerating performance of the second-stage expansion section 20a of the second cylinder, the first-stage expansion section 10a of the second cylinder is not connected to a JT circuit as a heat load, The temperature of the first-stage expansion section 10a of the cylinder is maintained at a stable and constant temperature to minimize the influence on the second-stage expansion section 20a of the second cylinder. The helium gas sequentially cooled in each pre-cooling heat exchanger and each JT heat exchanger is partially liquefied at the JT expansion valve 28, and becomes low-pressure cryogenic mist-like helium, which is the cryogenic liquid of the superconducting magnet device. It flows into the helium storage tank 32, and only liquid helium is stored. Liquid helium 31 due to helium gas content and heat penetration from the outside
The helium gas newly evaporated in the liquid helium storage tank evaporates and passes through the low pressure circuit of the JT circuit to the compressor main body 21.
Circulate back to.

FIG. 2 is a circuit diagram of a cryogenic refrigerating apparatus showing another embodiment. The same or corresponding parts as those shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In FIG. 2, reference numeral 24b is a fourth precooling heat exchanger provided in the second stage cold storage section of the first cylinder, and 26b is a fifth precooling heat exchanger provided in the second stage cold storage section of the second cylinder. In the cryogenic refrigerator configured as described above, the second pre-cooling heat exchanger 2
The gas in the JT circuit cooled in 4 is supplied to the fourth pre-cooling heat exchanger 2
It is further cooled at 4b. Similarly, the third precooling heat exchanger 2
The gas in the JT circuit cooled in 6a is further cooled in the fifth precooling heat exchanger 26b.

FIG. 3 is a partial cross-sectional view of an expansion portion showing another embodiment. The same or corresponding parts as those shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. Figure 3,
4, reference numerals 14 and 19a are second expansion cylinders, 14c is a cooling fin groove provided in a part of the inner diameter of each second cylinder, and 24 is a second expansion cylinder provided outside the second expansion cylinder 14. The pre-cooling heat exchanger 26a is a third pre-cooling heat exchanger also provided outside the second stage expansion cylinder 19a. In the cryogenic refrigerator configured as described above, the contact area between the refrigerant gas in each of the second stage cylinders 14 and 19a and the inner diameter surface of each cylinder is significantly increased by providing the fins, and the heat exchange efficiency is increased. Therefore, more refrigeration can be transmitted to the JT circuit via the second pre-cooling heat exchanger 24 and the third pre-cooling heat exchanger 26a attached to each cylinder.

[0017]

As described above, according to the cryogenic cooling device of the present invention, the compression unit and the expansion unit of the refrigerator main body are made to have two cylinders, the rotation phase angle of each cylinder is appropriately shifted, and the refrigeration take-out unit is provided. By distributing it to the expansion part of the cylinder, torque fluctuation can be minimized to reduce the required electric power, and vibration noise from the bearing part and the gear joint part can also be reduced, and the refrigerator can be further reduced. More stable refrigeration output can be transmitted from the main body to the JT circuit. In addition to taking out refrigeration not only from the expansion section but also from the cold storage section, a cooling fin groove is provided in a part of the inner diameter of the expansion cylinder to increase the efficiency of heat exchange with the refrigerant gas. The cooling device has the effect of being obtained.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a cryogenic cooling device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of a cryogenic cooling device according to a second embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view showing a preferred example of an expansion section.

FIG. 4 is a cross-sectional view of the expansion section shown in FIG.

FIG. 5 is a circuit diagram of a conventional cryogenic cooling device.

[Explanation of symbols]

10, 15 Expansion part of the first cylinder 20a 2nd expansion part of the 2nd cylinder 21 JT circuit compressor 22, 23, 25, 27 JT heat exchanger 22a, 24, 26a Pre-cooling heat exchanger 24b, 26b Pre-cooling heat exchanger 28 JT expansion valve 30 Superconducting magnet (cooled body) 32 Liquid Helium Storage Tank 33 heat shield plate 34 Vacuum insulation outer tank container

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F25B 9/00 395 F25B 9/02

Claims (5)

(57) [Claims] 1. A first pre-cooling heat exchanger and a second expansion which have a pair of refrigerating cycles in which the expansion section has a two-stage structure, and further have a heat exchange relationship with the first expansion section of one refrigeration cycle. To a Joule-Thomson circuit having a second pre-cooling heat exchanger in a heat exchange relationship with a section and a second expansion section in a refrigeration cycle on the other side and a third pre-cooling heat exchanger in a heat exchange relationship, and a Joule-Thomson circuit Cryogenic cooling device with connected liquid helium reservoir. 2. A vacuum adiabatic outer tank container having therein a liquid helium storage tank containing an object to be cooled, a refrigerator body,
And a cryogenic cooling device having a Joule-Thomson circuit having a precooling heat exchanger for heat exchange, which is connected to the vacuum insulated outer vessel and has a two-stage two-cylinder expansion section of the refrigerating machine body, The first stage expansion part of the first cylinder and the second
Refrigeration generated in the stage expansion section and the second stage expansion section of the second cylinder is cooled by Joule Thomson (hereinafter referred to as JT) through the first precooling heat exchanger, the second precooling heat exchanger, and the third precooling heat exchanger.
(Referred to as)) A cryogenic cooling device characterized in that heat is transferred to the refrigerant in the circuit. 3. A fourth precooling heat exchanger and a fifth precooling heat exchanger are provided in the second stage cold storage section of the first cylinder and the second stage cold storage section of the second cylinder of the refrigerator main body. The cryogenic cooling device according to claim 2. 4. The cryogenic cooling apparatus according to claim 2, wherein grooves are provided inside the second-stage expansion cylinder of the first cylinder and the second-stage expansion cylinder of the second cylinder of the refrigerator. 5. The cryogenic cooling device according to claim 2, wherein the regenerator of each refrigerator is arranged outside the expansion cylinder.